Calibrated electric-field imaging with Rydberg-state fluorescence and Autler-Townes splitting

TL;DR

This paper presents a high-contrast, self-calibrating method for spatially resolving millimeter-wave electric fields using Rydberg-state fluorescence and Autler-Townes splitting, applicable to complex field distributions.

Contribution

The authors introduce a robust, wide-range calibration technique employing a steady-state GKSL master equation for electric field imaging with Rydberg atoms.

Findings

Achieved high-contrast imaging with zero background in vapor cells.

Successfully reconstructed electric fields via Autler-Townes splitting.

Demonstrated imaging of standing-wave patterns and field engineering.

Abstract

We demonstrate a spatially resolved method for imaging millimeter-wave (mmWave) electric fields using Rydberg-state fluorescence in a warm atomic vapor. By utilizing a multi-photon ladder excitation scheme, we leverage a specific decay channel that remains dark in the absence of the mmWave field, resulting in high-contrast imaging with effectively zero background. Absolute calibration of the local electric field is achieved by reconstructing the Autler-Townes splitting of the Rydberg resonance across the imaging volume. To ensure robust field extraction across a wide dynamic range--including regimes where spectral features are not fully resolved--we employ a steady-state analysis based on the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation. We apply this technique to visualize standing-wave interference patterns within a vapor cell and demonstrate the ability to engineer local field distributions using structured dielectric reflectors. This approach provides a versatile and self-calibrating platform for the diagnostic imaging of high-frequency electromagnetic fields and the characterization of mmWave-optical interfaces.